I do not think the market reacted to the senate yesterday. A coincidence.
I do think the market may be <500 by the end of the day for other reasons. We are in a true correction now I believe. We won't see ATHs again for several days or weeks potentially.
No, it was well planned out. Whenever you want to make a big move (either up or down), it will have the best effect when everybody is on edge because there's an allegedly big "news event" going on. People will use the news to rationalize any ridiculous change and act on it. With no news, a sudden sharp rise or crash will be much better absorbed by the market.
proof of this is when the senate meeting started yesterday coincided with a huge dump.